The gouty tophus: a review

Abstract

The tophus is the cardinal feature of advanced gout. This review summarises recent research into the biology, impact and treatment of tophaceous gout. Microscopically, tophi are chronic foreign body granuloma-like structures containing collections of monosodium urate (MSU) crystals surrounded by inflammatory cells and connective tissue. Extracellular trap formation mediated by neutrophil interactions with MSU crystals may be a central checkpoint in tophus formation. Gouty tophi impact on many aspects of health-related quality of life. Tophi are also implicated in the development of structural joint damage and increased mortality risk in people with gout. Effective treatment of tophaceous gout requires long-term urate-lowering therapy, ideally to achieve a serum urate concentration of <5 mg/dL (300 μmol/L). Recent advances in gout therapeutics have expanded urate-lowering therapy options for patients with severe tophaceous disease to allow faster regression of tophi, improved health-related quality of life and, potentially, improved structural outcomes.